The present invention relates to an electronic device.
An electronic device of this type is known, for example, from PCT Publication No. 99/40285. The electronic module depicted in that publication includes a housing part having a plug-in part, a printed circuit board finished with electrical/electronic components being inserted into the housing part, the ends of the contact elements connected to the plug-in part being passed through contact openings of the printed circuit board in the interior of the housing part and being electrically connected to the contact openings.
In recent times, sensors have been increasingly used in motor vehicles, the sensors including impact- and vibration-sensitive components, such as micromechanically manufactured semiconductor sensor elements, which as a result of patterning have, configured in one plane, semiconductor patterns that are mechanically very sensitive and that quickly break in response to powerful impacts. If one of these impact- and vibration-sensitive components is mounted on a printed circuit board and is inserted into a housing part in accordance with the known design described above, the contact elements of the housing part extending through contact openings of the printed circuit board, then impact- and/or vibration-stresses arch transmitted undamped via the contact elements and the mounting elements of the housing part to the printed circuit board and the component. In response to powerful impacts, such as arise in a collision after a free fall, the micromechanical patterns are deformed by the inertial forces operating in that case beyond the breaking point of the material and in this way are destroyed.
As a result of the simply and economically designed electronic device, the vibrations and mechanical impacts operating on the housing part are transmitted to the printed circuit board and the components situated thereon only in very damped fashion. The printed circuit board having the electronic components is flexibly supported in the housing part by the electrical contact elements that electrically connect the housing plug connectors to the printed circuit board. For this purpose, the contact elements are furnished with elastically deformable segments. Damping elements manufactured separately from the contact elements damp the vibration of the spring-mass system. In this context, the damping elements may constitute, in particular, a low pass and may prevent the transmission of high frequency vibrations to the printed circuit board and the components located thereon. Because the spring suspension is simultaneously realized by the electrical contact elements, there is no need for using separate spring elements, such as spiral springs, for supporting the printed circuit board in the housing part. The electronic device may be manufactured simply and economically, it being possible to employ the assembly techniques that have been used heretofore.
As a result of the fact that the elastically deformable contact element segments, which are not inserted into the contact openings, may be deflected in an elastic fashion in at least one direction perpendicular to the printed circuit board, but preferably in all three directions in space, it is possible in accordance with demand to realize a flexible support of the printed circuit board in one, two, or all three directions in space.
It is especially advantageous if when being plugged in the printed circuit board is slipped through the opening of the housing part onto the ends of the contact elements such that the ends penetrate in a contacting manner into the contact openings. This may be carried out particularly easily and economically, because then it is not absolutely necessary, for generating the electrical contact, to solder the contact elements to the contact openings of the printed circuit board.
Stop elements may advantageously be provided, which limit a deflection of the elastically deformable segments, in the plug-in direction of the printed circuit board onto the ends of the contact elements. As a result of the stop elements, it can be achieved that the contact elements, when the printed circuit board is mounted, give way into the housing interior only a predefined amount. As soon as the elastically deformable segments strike against the stop elements, the ends of the contact elements are pressed through the contact openings of the printed circuit board.
The stop elements can be configured simply and economically by a fixed segment of the contact elements, which contacts the interior wall of the housing part, opposite the housing opening.
The end faces of the printed circuit board are separated from the interior walls of the housing part by a gap, which makes possible in the housing interior a certain freedom of movement of the printed circuit board, which is suspended on the contact elements. The damping elements may be inserted into this gap and may connect the edge area of the printed circuit board to the housing part. As a result of the width of the gap and the size and elasticity of the damping elements, a defined damping can be achieved.
In addition, an interior wall of the housing part may be provided with a step, the upper side of which, facing the printed circuit board, constituting a stop for the printed circuit board when it is pushed onto the contact elements. As a result of the step, it is achieved that the contact elements, in a predefined portion of their length, penetrate through the contact openings. The damping elements may then be arranged between the side of the printed circuit board facing away from the housing opening and the frame.
It is especially advantageous if the damping elements are constituted by an elastomer, especially a liquid silicon rubber. In this case, the damping elements, before or after the printed circuit board is plugged onto the ends of the contact elements can easily be inserted into the housing part using a dispenser. The damping can easily be adjusted through the point of application and the quantity of elastomer.
It is also advantageous at the location of the damping elements to provide flow stop elements for limiting the liquid silicon rubber that is still capable of flowing immediately after its application.